Traditionally there are fewer movies made with a warlock as the main character than there are with witches. In the movies with witches (and to some extent in folklore and all other stuff) the black cat is the companion. What is a warlocks companion? Is it an Owl (from Sword and the Stone)? If this gets moved to another area then so be it, which is fine, but I was just hoping for an answer.
Reality based answer, from someone who reads to much trivia: The male version of a witch isn’t a warlock, but simply a male witch. Cite, kinda. Thus, there is no reason to have a warlock fulfill the part of a witch. Warlock means “oath breaker”, and they practice black magic.
Movie based answer: A warlock is like a female witch. However, since the movies’ version of reality is a polyglot creature based on popular conception, the warlock is likely to be accompanied by an owl, a cat, or a raven.
Oh, and the reason why they might be accompanied by an owl is that owls have been the symbol of great wisdom, ever since Egypt, and so they accompany they who know a lot. That is what wizard means. The reason it was accompanying a warlock is that people use words like wizard and warlock interchangeably.
In fiction, witches have always been a traditional symbol of sex. That makes them far more attractive to write about - and portray visually - than warlocks.
But both are imaginary creatures, so they can be defined and portrayed in any way the writer wants. Witches can have black cats or any other animal as a familiar, or none at all. Warlocks can be male witches or other types of magicians and have any type of familiar as well.
Some writers like to copy other’s traditions; some like to strike off for themselves and invent variations on the theme. That’s the fun of writing fiction.
Maybe a raven. Odin had a couple of raven familiars as I recall.
In the movie Excaliber, I remember that Merlin had a bird companion. I think it was an owl?
[hijack] If the witch’s companion is a black cat, Then wouldn’t a priest’s companion be a white dog?[/hijack]